scholarly journals Electrofiltration improves dead-end filtration of hyaluronic acid and presents an alternative downstream processing step that overcomes technological challenges of conventional methods

2017 ◽  
Vol 17 (9) ◽  
pp. 970-975 ◽  
Author(s):  
Gözde Gözke ◽  
Frank Kirschhöfer ◽  
Carolin Prechtl ◽  
Gerald Brenner-Weiss ◽  
Nikolay Venelinov Krumov ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Downstream Processing ◽  
Dead End ◽  
Processing Step ◽  
Conventional Methods

scholarly journals Primary recovery of hyaluronic acid produced in Streptococcus equi subsp. zooepidemicus using PEG–citrate aqueous two-phase systems

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miguel Flores-Gatica ◽  
Héctor Castañeda-Aponte ◽  
Mónica Rebeca Gil-Garzon ◽  
Liliana Monserrath Mora-Galvez ◽  
Martin Paul Banda-Magaña ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Negative Impact ◽  
Fermentation Broth ◽  
Downstream Processing ◽  
Bottom Phase ◽  
Two Phase ◽  
Streptococcus Equi ◽  
Aqueous Two Phase Systems ◽  
Phase Systems ◽  
First Time

AbstractGiven its biocompatibility, rheological, and physiological properties, hyaluronic acid (HA) has become a biomaterial of increasing interest with multiple applications in medicine and cosmetics. In recent decades, microbial fermentations have become an important source for the industrial production of HA. However, due to its final applications, microbial HA must undergo critical and long purification processes to ensure clinical and cosmetic grade purity. Aqueous two-phase systems (ATPS) have proven to be an efficient technique for the primary recovery of high-value biomolecules. Nevertheless, their implementation in HA downstream processing has been practically unexplored. In this work, polyethylene glycol (PEG)–citrate ATPS were used for the first time for the primary recovery of HA produced with an engineered strain of Streptococcus equi subsp. zooepidemicus. The effects of PEG molecular weight (MW), tie-line length (TLL), volume ratio (VR), and sample load on HA recovery and purity were studied with a clarified fermentation broth as feed material. HA was recovered in the salt-rich bottom phase, and its recovery increased when a PEG MW of 8000 g mol−1 was used. Lower VR values (0.38) favoured HA recovery, whereas purity was enhanced by a high VR (3.50). Meanwhile, sample load had a negative impact on both recovery and purity. The ATPS with the best performance was PEG 8000 g mol−1, TLL 43% (w/w), and VR 3.50, showing 79.4% HA recovery and 74.5% purity. This study demonstrated for the first time the potential of PEG–citrate ATPS as an effective primary recovery strategy for the downstream process of microbial HA.

Hyaluronic acid degradation during initial steps of downstream processing

2009 ◽  
Vol 28 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Chiara Schiraldi ◽  
Lucia Andreozzi ◽  
Iolanda Marzaioli ◽  
Sara Vinciguerra ◽  
Alberto D’Avino ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Downstream Processing ◽  
Acid Degradation

scholarly journals Yeast Cell Cake Characterization in Alcohol Solution for Efficient Microfiltration

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 89
Author(s):  
Nobuyuki Katagiri ◽  
Keisuke Tomimatsu ◽  
Keiichi Date ◽  
Eiji Iritani
Keyword(s):  
Membrane Filtration ◽  
Ethanol Concentration ◽  
Fermentation Broth ◽  
Downstream Processing ◽  
Alcohol Concentration ◽  
Yeast Cells ◽  
Alcohol Fermentation ◽  
Dead End ◽  
Flux Decline ◽  
Filtration Properties

Microfiltration is widely used to remove microbial cells from the fermentation broth in the downstream processing of biotechnological products. Because filtration behaviors are strongly affected by the characteristics of the microbial cell cake formed on the surface of the membrane, insights into the cake structure facilitate the design and operation of filter equipment and membranes. In the alcohol fermentation process using a yeast strain, the cake characteristics are considered to be complicated because yeast cells are strongly influenced by external factors such as filtration pressure and alcohol concentration. In this study, we evaluated the membrane filtration properties, in particular the cake characteristics of a yeast suspension containing alcohol. Microfiltration experiments were performed in the dead-end filtration mode using yeast suspensions with several ethanol concentrations (0–20 wt%) under constant pressure. Flux decline behaviors caused by yeast cake were put in a similar form for 0–15 wt% ethanol concentrations. In contrast, a severe flux decline was observed for the suspension with 20 wt% ethanol concentration. It was also observed that in the membrane filtration of yeast cells with 20 wt% ethanol concentration, the cake structure became denser and the filtration resistance remarkably increased because of cellular destruction. Furthermore, the yeast cake exhibited a high compressibility in the solution containing a 20 wt% ethanol concentration. Therefore, the filtration rate of the alcoholic fermentation broth is not significantly improved by increased pressure due to the increase in the cake resistance.

scholarly journals INVESTIGATION ON DOWNSTREAM PROCESSING OF INDUSTRIAL SCALE OF FLEXIRUBIN PRODUCTION USING SUPERPRO DESIGNER

2021 ◽  
Vol 83 (2) ◽  
pp. 37-45
Author(s):  
Muhammad Zainuddin Arriafdi ◽  
Mohd Helmi Sani ◽  
Wan Azlina Ahmad ◽  
Muhd Nazrul Hisham Zainal Alam
Keyword(s):  
Operating Cost ◽  
Downstream Processing ◽  
Capital Cost ◽  
High Yield ◽  
Separation Processes ◽  
Dead End ◽  
Strain Process ◽  
Filtration Unit ◽  
High Degree ◽  
Process Simulator

The aim of this work is to utilize a process simulator SuperPro Designer v5.5 (Intelligent, NJ, USA) for investigation on the most optimum scenario for the recovery of flexirubin pigment that was produced from a fermentation process using Chryseobacterium artocarpi strain. Process flow sheeting was based on the production of 300 kg per annum of flexirubin. Production phase at 1000 L bioreactor (including steps for the inoculum development) and different scenarios/routes for recovery of flexirubin were considered. SuperPro designer process simulator allowed for the computation of overall operating cost and capital cost under various operating parameters. Results from simulation shows that all proposed downstream processing routes is capable of achieving a high degree of flexirubin recovery yield i.e. at least 94% (or greater).  Operating cost was relatively low as the overall quantity of flexirubin was rather small. Capital cost for equipment purchasing however highly depending on the selection of unit procedures for recovery of flexirubin. Centrifugation unit accelerated the separation processes but it is costly compared to the dead-end filtration unit. The latter was found to be the bottleneck for the optimization step where high yield of flexirubin can be warranted at reduced capital cost by at least 40%.

Spin-polarized Scanning Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 768-769
Author(s):  
Kazuyuki Koike ◽  
Hideo Matsuyama
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Speed ◽  
Magnetic Thin Films ◽  
Electron Spin Polarization ◽  
Acquisition Time ◽  
Magnetization Direction ◽  
Spin Polarized ◽  
Conventional Methods ◽  
Scanning Electron

Spin-polarized scanning electron microscopy (spin SEM), where the secondary electron spin polarization is used as the image signal, is a novel technique for magnetic domain observation. Since its first development by Koike and Hayakawa in 1984, several laboratories have extensively studied this technique and have greatly improved its capability for data extraction and its range of applications. This paper reviews the progress over the last few years.Almost all the high expectations initially held for spin SEM have been realized. A spatial resolution of several hundreds angstroms has been attained, which is nearly one order of magnitude higher than that of conventional methods for thick samples. Quantitative analysis of magnetization direction has been performed more easily than with conventional methods. Domain observation of the surface of three-dimensional samples has been confirmed to be possible. One of the drawbacks, a long image acquisition time, has been eased by combining highspeed image-signal processing with high speed scanning, although at the cost of image quality. By using spin SEM, the magnetic structure of a 180 degrees surface Neel wall, magnetic thin films, multilayered films, magnetic discs, etc., have been investigated.

The Need Inventory of Sensation Seeking (NISS)

2012 ◽  
Vol 28 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Marcus Roth ◽  
Philipp Hammelstein
Keyword(s):  
Sensation Seeking ◽  
Reliability And Validity ◽  
Assessment Method ◽  
Factorial Structure ◽  
Conventional Methods ◽  
New Research ◽  
Sensation Seeking Scale ◽  
Temperamental Trait ◽  
Nonclinical Study

Based on the conception of sensation seeking as a need rather than a temperamental trait ( Hammelstein, 2004 ), we present a new assessment method, the Need Inventory of Sensation Seeking (NISS), which is considered to assess a motivational disposition. Three studies are presented: The first examined the factorial structure and the reliability of the German versions of the NISS; the second study compared the German and the English versions of the NISS; and finally, the validity of the NISS was examined in a nonclinical study and compared to the validity of conventional methods of assessing sensation seeking (Sensation Seeking Scale – Form V; SSS-V). Compared to the SSS-V, the NISS shows better reliability and validity in addition to providing new research possibilities including application in experimental areas.

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